Pressure and Temperature Spin Crossover Sensors with Optical Detection

Iron(II) spin crossover molecular materials are made of coordination centres switchable between two states by temperature, pressure or a visible light irradiation. The relevant macroscopic parameter which monitors the magnetic state of a given solid is the high-spin (HS) fraction denoted nHS, i.e., the relative population of HS molecules. Each spin crossover material is distinguished by a transition temperature T1/2 where 50% of active molecules have switched to the low-spin (LS) state. In strongly interacting systems, the thermal spin switching occurs abruptly at T1/2. Applying pressure induces a shift from HS to LS states, which is the direct consequence of the lower volume for the LS molecule. Each material has thus a well defined pressure value P1/2. In both cases the spin state change is easily detectable by optical means thanks to a thermo/piezochromic effect that is often encountered in these materials. In this contribution, we discuss potential use of spin crossover molecular materials as temperature and pressure sensors with optical detection. The ones presenting smooth transitions behaviour, which have not been seriously considered for any application, are spotlighted as potential sensors which should stimulate a large interest on this well investigated class of materials

Modélisation d'un réacteur RF à couplage capacitif en mélange Ar-O2 dans les conditions utilisées pour le procédé de dépôt par voie plasma d'oxyde d'étain

PARIS-BIUSJ-Thèses (751052125) / SudocPARIS-BIUSJ-Physique recherche (751052113) / SudocSudocFranceF

Stable Polymerized Acrylic Acid coating deposited on Polyethylene (PE) films in a low frequency discharge

Plasma polymerized acrylic acid (PPAA) coatings were deposited on PE films, in a 70 kHz low pressure plasma reactor, at various plasma powers. The COOH retention of PPAA coatings and its stability to washing in water were investigated by XPS, WCA (water contact angle), FTIR, ellipsometry and SEM analyses. The results have shown that the use of higher powers leads to an increase of the stability of the coating due to a high degree of cross-linking. Under optimized conditions, it is possible to obtain stable PPAA coatings which resist to washing with a COOH retention rate of 15% on PE, which is much higher than the coating deposited in a 13.56 MHz discharge. This high stability of the coatings observed in the low frequency discharge, which is somewhat similar to DC glow discharges, is probably due to the ions which play an important role in the cross linking process of the coatings. Optical emission spectroscopy measurements (OES) have shown good correlation between the CO density in the gas phase and the carboxylic content of PPAA coating

Education of students and citizens for process development

International audienceEducation may be a powerful and efficient tool to promote as well to enhance new material creation as well as new processes to produce them or training to increase society acceptability. New Information and Communication Technology in Education can help the promotion of the conception, the production and the use of new materials and processes within society. Besides, the use of project work such as Controversy studies in Energy and Environment also contribute to form students to the implementation of new ideas and technologies

Education of students and citizens for process development

Education may be a powerful and efficient tool to promote as well to enhance new material creationas well as new processes to produce them or training to increase society acceptability (Delebarre,2021). New Information and Communication Technology in Education can help the promotion of theconception, the production and the use of new materials and processes within society. Besides, theuse of project work such as Controversy studies in Energy and Environment also contribute to formstudents to the implementation of new ideas and technologies (Delebarre and Wei, 2019)It has been a long time since teachers have been looking for new education methods to improvelearner motivation and knowledge transfers and thus the acquisition of skills. Furthermore, newmaterials and new processes often need experimental and theoretical knowledge to characterize thesearched properties of materials and then to design the process to produce it. Fortunately, Informationand Communication Technology in Education can help in improving the teaching content devoted toattendees such as (i) future or present researchers in charge of the conception of new materials aswell as new processes to produce them; (ii) future or present engineers able to design the plants toproduce these new materials; (iii) citizens that may enhance the acceptability of innovations and theuse of them. Moreover, education to conceive, to design, to produce and to use new products andprocesses can be helped and supported by massive open online course (MOOC) or small private onlineclasses (SPOC).This paper aims at showing the motivation and at demonstrating the effectiveness of new methods oflearning that may serve the conception of products and processes that produce them. For instance,new methods and tools were used to improve thermodynamics teaching to avoid intrinsic difficultiesof this matter and to take advantage of new generation appetence for new technologies. Mines Parishas thus conceived and managed several MOOCs in Energetics (“Problèmes Energétiques Globaux”) aswell as Thermodynamics (“Conversion Thermodynamique de la Chaleur” and “ThermodynamiqueExpérimentale”). This paper proposes firstly returns of experience from these MOOC, such asattendance distribution, examination attendance, successful student percentages and quality andeffectiveness of learning experience and also their use as self-paced training cursus or SPOC interactivetools (Delebarre et al., 2017, Delebarre et al., 2018).Then it describes the MOOC "Thermodynamique Expérimentale" devoted to the teaching ofexperimental thermodynamics for attendants ranging from students (Master or PhD), to personal orcustomer individuals of process design and maker companies or new fluid or product producercompanies. This MOOC may be particularly useful to consider the adaptation of infrastructuresconceived for Liquefied Natural Gas to Liquefied Biogas or to characterize new materials/fluids andprocesses issued from refinery of biomass or to evaluate Carbon Capture Utilization and Storageaccording to industrial plants. This MOOC includes very specific contents such as the possibility of virtual practical experimental works by each learner. Some data on examination attendance, successfulstudent percentages and quality and effectiveness of learning experience obtained during threesessions performed on FUN Platform are given.The authors would like to thank Renaud Gicquel, professor formely in Mines Paris, author of the MOOC“Problèmes Energétiques Globaux”, Christophe Coquelet (IMT Mines Albi) co-author of the MOOC“Thermodynamique Expérimentale” and Nicolas Vion filmmaker of the above cited MOOC

An evaluation of the carcinogenic potential of five man-made vitreous fibers using the intraperitoneal test

International audienceThe objective of this study was to evaluate the potential carcinogenic hazard of five man-made vitreous fibers (MMVF) following the recommendations of the dust subgroup of the German Maximale Arbeitsplatz Konzentration (MAK) Commission. This was done by rating the tumors arising from intraperitoneal injection in the rat, relative to the number of injected fibers with length (L) > 5 mu m, diameter (Di 5 contained in the sample. Fibers from glass and stone wools were selected for this evaluation. At the outset of this study, because of their chemical composition, the substances tested were considered new-generation insulation wool fibers. As an example, their "solubility" as measured in vitro at pH 7.4 was higher than those of insulation wool fibers used at that time. The samples have been specially manufactured and processed in order to improve their concentration in fibers fitting the criteria of length and diameter required by the protocol of this study. This was done for several purposes. The first one was to test fibers that are as similar as possible to those encountered at the workplace (median diameter below I mu m and median length between 10 and 15 mu m), in order to facilitate extrapolation to the human situation. The second one was to allow injection of the highest possible dose of fibers under a tolerable volume, since too large a volume and/or too high a number of injections may increase the risk of artifactual responses. In addition, the highest doses were selected on the basis of the recommendations of the dust subgroup of the German MAK Commission along with our decision to limit the number of injections to two. Female Wistar rats were used as a model. They received an intraperitoneal injection of various masses (from 0.7 to 55 mg) of sample, and then were followed during an observation period of 130 wk. The positive controls (long-fiber crocidolite from 0.005 to 0.5 mg) exhibited a significant dose-related occurrence of mesotheliomas. According to the MAK Commission criteria, a carcinogenic potential was demonstrated for fiber H (at the highest dose, 55 mg). The other fibers (A, C, F, and C) did not show any statistically significant carcinogenic potential at the tested doses

Numerical modeling of capacitively coupled hydrogen plasmas: effects of frequency and pressure

International audienc